Winter flowering begonias (Begonia × hiemalis) may be sold under the trade names Rieger begonia or Elatior begonia. Those names are associated with 20th century breakthroughs in breeding and have become attached to these plants, though they are no longer considered correct names for the hybrids as a group.  Complex hybrids of diverse, tuberous-rooted, plants, these semi-tuberous begonias do not fit neatly into the three growing categories and have inconsistent roots. They captured the hearts of growers for their winter bloom cycle with large, mostly double or semi-double flowers. Plants, including almost 500 cultivars, can be found for sale year round and are typically kept as a temporary decoration and then discarded.

Light:

They need bright, filtered light with no direct sunlight. The light near an east-facing window is ideal, or further from a south- or west-facing window.

Temperature:

These begonias grow best at 60 to 65º F. to extend the period of flowering. Avoid hot and cold drafts near heat vents or cold doors and windows. Do not expose to temperature below 50º F.

Watering and humidity:

When the top inch of soil feels dry to the touch, water thoroughly in the morning using tepid water. Discard excess water from the run-off dish after 15 minutes.

A relative humidity above 50% is preferred to successfully grow winter flowering  begonias. Provide additional humidity by misting twice daily, standing plants on shallow trays filled with moistened pebbles and/or using a humidifier. A simple hygrometer kept in the area of the plant will help you to monitor air moisture.

Read more about care of this plant in our Guide to Winter-flowering Begonia.

Courtesy of the NYBG Plant Information Service